Pressure applying apparatus



A 6, 1943. J. s. RODGERS PRESSURE APPLYING APPARATUS Original Filed Feb.18, 1938 [VVENTOE JZIMESJZEODGEEJ Arrae/vEYs Patented Apr. 6, 1943PRESSURE APPLYING APPARATUS James S. Rodgers, St. Louis Park, Minn.,assignor to Rodgers Hydraulic Incorporated, St. Louis Park, Minn., acorporation of Minnesota Original application February 18, 1938, SerialNo. 191,277. Divided and this application January 10, 1942, Serial No.426,365

3 Claims.

This application is a division of my pending application Serial No.191,277, filed under date of February 18, 1938 (now abandoned).

The present application is directed more specifically toa dual springmechanism for returning the ram of a hydraulic press to its normalinoperative position within the ram cylinder. A hydraulic apparatus ofthe type herein disa Y closed; is often called upon to impart a long 7having a relatively long stroke in proportion to the length of the powercylinder, and in which spring, means is provided for returning the ramto its normal inoperative position following the power stroke.

An important object of the present invention therefore is to provide apressure applying apparatus comprising a cylinder having a ram mountedtherein and provided with spring means for returning the ram to itsnormal inoperative position, at the termination of each power stroke,said spring means being so arranged within the cylinder that the returnmovement of the ram maybe constant and uniform, when the pressure fluidis released to permit the return of the ram.

Aiurther object is to provide a pressure applying apparatus comprising acylinder having a ram mounted for reciprocal movement therein, and; apair of springs being mounted within the cylinder ior returning the ramto its normal inoperative position, said springs being of differentdiameters whereby one end of one of said springs may be disposed withinthe adjacent end of theother of said springs, and a suitable cupshapedretainer being provided for retaining the adjacent ends of the springsin axial telescoping relation.

. A further object is to provide an apparatus of the classdescribedcomprising a pair of springs for retracting the ram after eachpowerstroke, and said springs being substantially uniform in strengthand having their adjacent ends telescoped, whereby the overall length ofthe power cylinder may be reduced in proportion to the length of thestroke of the ram.

Other objects of the invention residein the novel arrangement of thesprings within the cyl- =.-in d er whereby the expansionand contractionof said pr n a u tam r will be substantially uniform; in the provisionof a cupshaped member within the cylinder for retaining the adjacentends of the springs in axial telescoping relation, and whereby saidmember in addition to retaining said springs in proper position withinthe cylinder, may also function as a limit stop for limiting forwardmovement of the ram, thereby to prevent damage to the springs by theram; in the novel arrangement of the springs within the cylinder wherebythey cannot accidentally cause injury to workmen, should one becomebroken while under pressure; and in the simple and inexpensiveconstruction of the apparatus whereby it readily lends itself formanufacture in quantity production at a low cost.

Other objects of the invention will appear from the followingdescription and accompanying drawing and will be pointed out in theannexed claims.

In the accompanying drawing there has been disclosed a structuredesigned to carry out the various objects of the invention, but it is tobe understood that the invention is not confined to the exact featuresshown, as various changes may bemade within the scope of the claimswhich follow.

In the drawing:

Figure 1 is a view showing the invention embodied in a power press ofthe type disclosed in the hereinbefore mentioned-pending application;and

Figure 2 is an enlarged detail sectional view showing the ram head atthe limit of its forward movement against the spring retainer, and alsoshowing the springs as when under maximum pressure of the ram.

In the selected embodiment of the invention herein disclosed, there isillustrated in Figure 1, for purposes of disclosure, a portion of ahydraulic power press comprising a main supporting frame, generallydesignated by the numeral 2, which may be composed of side beams 3 andcross-members 4 and 5. A suitable engine, not shown, may be mounted atthe front end of the frame 2, and is adapted to be operatively connectedto a drive shaft through a transmission II and universal joint 13. Therear end of the shaft I4 is shown having a chain drive I1, operativelyconnecting it to a crank shaft l9, adapted to operate one or more pumps,not

'shown, which may be located within a suitable housing 2].

d An important object of the present invention resides in'the uniqueconstruction of the power applying means of the apparatus which, asshown in the drawing, comprises a cylinder, generally designated by thenumeral 35. The ends of the cylinder 35 are closed by suitable heads orend walls 36 and 31, the head 31 being operatively mounted in a plate 39having tension rods 38 engaged thereto and a member generally designatedby the numeral 34. The plate 39 and member 34 are suitably mounted uponand secured to the main supporting frame 2 by suitable means, not shown.

A thrust member 25, shown mounted in spaced relation to the member 34,and a suitable work table 22 is disposed between the member 34 andthrust member 25. The work to be operated upon, as for example tractionlinks 29, are supported on the work table 22 against the thrust member25, as will be clearly understood by reference to Figure 1.

A suitable ram 41 is mounted for reciprocal movement within the cylinder35, and is provided at its inner end with a piston head 46, which fitsthe bore of the cylinder, as shown. The opposite end of the ram projectsthrough a guide opening in the end wall 36 of the cylinder, and may beprovided with a suitable work engaging head 43 adapted to engage one endof a rod 49, whose opposite end may be engaged with the work, as forexample a wrist pin A, of a traction link.

A pipe or conduit I I3 leads from the pump, not shown, to one end of thecylinder 35 back of the ram head 46, whereby when the pump is operated,fluid is pumped into the cylinder back of the ram head 45, whereby theram is moved forwardly against the work, as will be understood byreference to Figure 1. A suitable fluid control valve, not shown in thedrawing, may be provided in connection with the conduit H3 to releasethe fluid from the cylinder 35 at the termination of the working strokeof the ram.

An important feature of the present invention resides in the novel meansprovided within the cylinder for returning the ram to its normalinoperative position, at the termination of each power stroke.

The means provided for thus returning the ram comprises a pair ofsprings and 52. The spring 5| has one end seated against the ram head 46and its opposite end against an outwardly turned flange 54 provided onone end of a cup-shaped spring retaining member 53. The member 53 isadapted to fit into one end of the relatively larger spring 5|, and isprovided at its opposite end with an inturned flange 55 against whichthe adjacent end of the relatively smaller spring 52 is seated. Theopposite end of the spring 52 is seated against the end wall of thecylinder 35, as shown in the drawing.

The member 53 retains the adjacent ends of the springs 5| and 52 inaxial telescoping relation, and the cylindrical wall thereof serves toguide the coils of the springs in such a manner as to prevent anytendency of the springs to buckle, when under compression. The member 53is also free to move longitudinally within the cylinder and with respectto the ram 41, which it will be noted, passes through a suitable openingprovided in the left hand end of the member 53, when viewed as shown inthe drawing.

Another important feature of the invention resides in the constructionof the springs 5| and 52, which are so designed that they aresubstantially uniform in strength. In other words, the

relatively larger spring 5| is made of a heavier wire than the smallerspring 52' because of its greater diameter, whereby the two springs aresubstantially equal in strength. By so designing the springs 5| and 52,when the ram is moved forwardly in its power stroke, the springs 5| and52 will compress in substantially the same degree, thereby causing theretaining member 53 to move forwardly within the cylinder until it mayreach the position shown in Figure 2. When thus positioned, therelatively smaller spring 52 may be completely enclosed within theretainer 53, and the relatively larger spring 5| will be coiled aboutthe member 53 between the ends thereof. Thus it will be noted that themember 53 provides a limit stop for the forward movement of the ram 4'!and, at the same time, properly retains the springs in their telescopingrelation, as clearly illustrated in the drawing.

By making the two springs substantially equal in strength, the springswill always flex simultaneously and at substantially the same degree oramount, when the ram is reciprocated within the cylinder. I have foundthat by proportioning the springs as herein set forth, the returnmovement of the ram from an operative to an inoperative position may beexpedited, and with the assurance that the springs will always beretained in substantially axial alinement with the ram 41.

Another feature of the invention resides in the arrangement of thesprings within the cylinder, whereby should one of the springsaccidentally snap or become broken, as a result of pressure thereon,such damaged'spring cannot cause damage to a workman or other personstationed adjacent to the apparatus, because the springs are completelyconfined within the cylinder, as will be understood by the drawing. Theretainer 53 so guides the coils of the relatively larger spring 5| thatthey cannot frictionally engage or rub against the wall of the cylinder,whereby excessive wear is reduced to a minimum, and the life of thespring prolonged.

It will be apparent to those skilled in the art that I have accomplishedat least the principal objects of my invention, and it will also beapparent to those skilled in the art that the embodiments hereindescribed may be variously changed and modified, without departing fromthe spirit of the invention, and that the invention is capable of usesand has advantages not herein specifically described; hence it willb'e'appreciated that the herein disclosed embodiments are iilustrativeonly, and that my invention is not limited thereto.

I claim as my invention:

1. A cylinder having means at one end for supplying a fluid pressurethereto, a ram mounted for reciprocal movement within the cylinder andhaving a piston head at one end, a spring coiled about the ram andhaving one end seated against one end of the cylinder, a cup-shapedretainer mounted within the cylinder and providing an abutment for theopposite end of said spring, a

relatively larger diametered spring having one pressure when the pistonis actuated by-fluid pressure, and the over-all length of said retainerbeing slightly greater than the combined overall length of said springswhen the springs are completely compressed, whereby said retainer mayalso function to provide an abutment stop for the ram when the ram is atthe limit of its forward movement.

2. A cylinder having means at one end for delivering a pressure fluidthereto, a ram mounted within the cylinder and having one end projectingfrom the opposite end of the cylinder, a piston head secured to theinner end of the ram, means within the cylinder for returning the ram toits normal inoperative position, said means including a spring which iscoiled about the ram and has one end seated against one end of thecylinder, a cup-shaped retainer mounted for axial movement within thecylinder and having an aperture for receiving the ram, said member beingfitted over the opposite end of the spring and having an annularinwardly turned flange against which the adjacent end of said spring isseated, a relatively larger spring within the cylinder having one endseated against the piston head and having its opposite end fitting oversaid cupshaped member, said member having an outwardly turned flangeagainst which the opposite end of the relatively larger spring is seatedand whereby the adjacent ends of said springs are retained intelescoping relation, and said springs being substantially equal instrength, whereby the flexing thereof, when compressed by forwardmovement of the ram, will be substantially uniformly distributed betweenall of the coils of said springs, thereby increasing the useful life ofthe springs, said cup-shaped retainer, in addition to supporting thetelescoped ends of the springs, providing an abutment stop for the ramwhen at the limit of its forward movement, thereby to avoid damage tothe springs.

3. A cylinder having means at one end for delivering a pressure fluidthereto, a ram mounted within the cylinder and having one end projectingfrom the opposite end of the cylinder, a piston head secured to theopposite end of the ram, a pair of springs mounted within the cylinderfor returning the ram to its normal inoperative position, one of saidsprings being coiled about the ram and having one end seated against oneend of the cylinder, a cup-shaped member mounted within the cylinder andhaving an aperture for receiving the ram, said member having an annularinwardly turned flange against which the opposite end of said spring isseated, a relatively larger spring within the cylinder having one endseated against the piston head, and an outwardly turned flange on theopposite end of said member against which the opposite end of therelatively larger spring is seated and whereby the adjacent ends of saidsprings are disposed in telescoping relation. and the overall length ofsaid member being slightly greater than the combined overall lengths ofsaid springs, when the springs are completely compressed, whereby saidmember may also function to provide an abutment stop for the ram, whenat the limit of its forward movement, and whereby damage to the springsis minimized.

JAMES S. RODGERS.

